The price of the Nauticam viewfinder put me off buying one for my GH4 . INON make a unit that is less than half the price,unfortunately it is not made for the GH4 housing. After a bit of research I was informed by my local INON agent that the barrel of the viewfinder is 20mm .Success !! I removed the cir-clip that holds the body to the mount ,measured the dimensions of the adapter and made one with the outer dimensions to slide into the GH4 mounting hole. One hour on the lathe and time to test. Fit the revised mount suck a vacuum ,come back half an hour later and light still green. Just back from 9 days at Lembeh and worked like a charm. No modification to viewfinder and original ring can go straight back if no longer required.
